Transformation of isosteviol lactam by Fungi and the suppressive effects of its transformed products on LPS-induced iNOS expression in macrophages

Bo Hon Chou, Li Ming Yang, Shwu Fen Chang, Feng-Lin Hsu, Li Hsuan Wang, Wen Kuang Lin, Pan Chun Liu, Shwu Jiuan Lin

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

From the screening of 21 microbial strains, Absidia pseudocylindrospora ATCC 24169 and Aspergillus niger BCRC 32720 were found to reproducibly transform isosteviol lactam (4α-carboxy-13α-amino-13,16-seco-ent-19- norbeyeran-16-oic acid 13,16-lactam) (3) into various compounds. Preparative-scale transformation of 3 with Abs. pseudocylindrospora yielded two new hydroxylated compounds (4 and 5), with conservation of the lactam ring. Preparative-scale transformation of 3 with Asp. niger afforded seven new compounds, 6 and 9 - 14, together with the known compounds 7 and 8. A single-crystal X-ray diffraction experiment confirmed the structure of 14. The suppressive effects of compounds 1 - 14 on the lipopolysaccharide-induced expression of the inducible nitric oxide synthase gene in RAW 264.7 macrophages were examined by a reverse-transcription real-time PCR analysis. With the exception of 7, all other compounds significantly reduced levels of iNOS mRNA relative to control cells, which were induced by LPS alone. Compounds 2, 3, and 5 were similar in activity to dexamethasone, while 9 was more potent.

Original languageEnglish
Pages (from-to)1379-1385
Number of pages7
JournalJournal of Natural Products
Volume74
Issue number6
DOIs
Publication statusPublished - Jun 24 2011

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ASJC Scopus subject areas

  • Complementary and alternative medicine
  • Molecular Medicine
  • Organic Chemistry
  • Analytical Chemistry
  • Pharmaceutical Science
  • Pharmacology
  • Drug Discovery

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